The present invention relates to the discovery of devices such as Ethernet phones on a network such as a LAN (Local Area Network) or other network.
The present invention relates to the process of discovery of the devices on a network, that is a network of electronic devices comprising, for example, workstations, personal computers, servers, hubs, routers, bridges, switches, (hereinafter referred to as devices of the network), and links between these devices which may be in the form of physical cable or wireless links. The network may be a local area network (LAN), such as an Ethernet network, wide area network (WAN) or other types, including wireless networks, and may operate in accordance with any desired protocol.
Computers and other devices connected to a network may be managed or unmanaged devices. A managed device has processing capability which enables it to monitor data traffic sent from, received at, and passing through the ports of the device. Monitored data associated with the ports of the network device is stored in memory on the network device. For example, data relating to the origin of a data packet which is received at a port is stored along with the identity of the relevant port.
After such a network has been installed, it is desirable for the person appointed network manager to be able to understand the technical operation of the network. In known network management systems, the manner in which the relevant data is retrieved from the managed devices, compiled and displayed (“discovered”) has been problematic in several respects. One problem is that the data does not provide information about unmanaged devices.
The topology of the network may be deduced by operation of the network manager's computer by the process of discovery in which each of the devices of the network are interrogated to thereby produce on a network manager's workstation details of the network and its operation, preferably in the form of a network map which may be displayed on a visual display unit showing the devices and links between the devices. At its simplest, and where the device is a “managed” device, this information is usually provided by interrogation using a known protocol, such as, but not limited to, the SNMP (Simple Network Management Protocol), of the so-called ‘agent’ of each device which stores the device's unique MAC address, the type of device and the MAC addresses embedded in the data passing into a particular port which thereby gives the MAC addresses of the origin of the data and hence the MAC address of the devices which are connected to the ports directly or indirectly.
It has recently been proposed to include so called Ethernet telephones in networks (particularly LANs), in addition to the usual workstations, routers and switches. These Ethernet telephones (which may be controlled by a telephone controller, usually a network call processor (NCP)) allow one to use the existing wiring or other network medium to implement a telephone system. This is particularly useful in a business environment where a single set of cables or other medium may be provided to connect both the computer network and the telephone network.
It is clearly desirable that the network manager of the computer network should be able to similarly view the availability and placement (i.e. the topology) of phones on this same network.
A particular difficulty in meeting this objective is that Ethernet phones may not be managed, that is they do not carry an agent as described above. Thus a typical discovery process will not be able to obtain sufficient information about the telephones for details of them to be available to the network manager. At best, they will appear as “generic” devices which have only a MAC address associated with them.
Furthermore, in a typical arrangement of Ethernet phones, a user's PC (personal computer) will be connected through the Ethernet phone to the same port of the network device. Typical discovery processes would simply see two MAC addresses on the same port of the network device, which it would know is impossible, and hence will either (a) highlight the error, or (b) just display them both connected to the port (which is incorrect), or (c) display some item such as a cloud between the port and the phone/PC.